642716777 has 2 divisors, whose sum is σ = 642716778. Its totient is φ = 642716776.

The previous prime is 642716771. The next prime is 642716783. The reversal of 642716777 is 777617246.

It is a balanced prime because it is at equal distance from previous prime (642716771) and next prime (642716783).

It can be written as a sum of positive squares in only one way, i.e., 347598736 + 295118041 = 18644^2 + 17179^2 .

It is a cyclic number.

It is not a de Polignac number, because 642716777 - 2¹⁶ = 642651241 is a prime.

It is not a weakly prime, because it can be changed into another prime (642716771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321358388 + 321358389.

It is an arithmetic number, because the mean of its divisors is an integer number (321358389).

Almost surely, 2^642716777 is an apocalyptic number.

It is an amenable number.

642716777 is a deficient number, since it is larger than the sum of its proper divisors (1).

642716777 is an equidigital number, since it uses as much as digits as its factorization.

642716777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 691488, while the sum is 47.

The square root of 642716777 is about 25351.8594387078. The cubic root of 642716777 is about 862.9915543456.

The spelling of 642716777 in words is "six hundred forty-two million, seven hundred sixteen thousand, seven hundred seventy-seven".